Impaired peak oxygen uptake in older patients with heart failure: a systematic-review and meta-analysis
Bibliographic record
Abstract
Abstract Background Reduced peak exercise oxygen uptake (VO2peak) is a hallmark feature of heart failure (HF). Despite its importance, few studies have measured VO2peak in older HF patients. Purpose Aim 1) To assess VO2peak in older (mean age ≥ 65 yrs) HF patients and controls (CON); Aim 2) To compare VO2peak in HF patients across the older age continuum (i.e., young-old, YO, 60-69 yrs vs. middle-old, MO, 70-79 yrs vs. old-old, OO, ≥ 80 yrs). Methods The PubMed database was searched (1967-May 2024) for studies meeting the following inclusion criteria: 1) HF (mean age ≥ 65 yrs); 2) VO2peak assessed by maximal cardiopulmonary testing; and 3) non-HF CON (Aim 1 only). For Aim 2, included studies needed to compare VO2peak between YO vs. MO or MO vs. OO HF patients. A random effects meta-analysis was conducted comparing VO2peak (and its Fick determinants if reported) in HF vs. CON (Aim 1) and VO2peak between YO vs. MO and MO vs. OO patients with HF (Aim 2). Results are presented as weighted mean differences (WMD) and their 95% confidence intervals (95% CI). Results 38 studies out of 2,788 screened articles met our inclusion criteria. For Aim 1, 30 studies were included (HF, n=1,093, mean age: 70 yrs, 46% females and CON, n=942, mean age: 69 yrs, 52% females). Compared to CON, peak exercise VO2, cardiac output and heart rate were significantly lower in HF with no significant difference between groups for peak exercise stroke volume or arterial-venous content O2 content difference (Figure 1). For Aim 2, 8 studies were analysed: YO, n=3,394 vs. MO, n= 2,445 and MO, n=877 vs. OO, n= 271. VO2peak significantly decreased by 1.5 mL/kg/min and 1.2 mL/kg/min between MO and YO, and OO vs. MO, respectively (Figure 2). Conclusion Older HF patients experience a marked reduction in VO2peak compared to age-matched controls. This decrease is primarily due to a lower peak exercise heart rate and reduced cardiac output. VO2peak in patients with HF decreases progressively with age. Future studies are required to examine the impact of exercise training to improve VO2peak and exercise cardiac function in older patients with HF.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.008 | 0.022 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.016 | 0.023 |
| Bibliometrics | 0.005 | 0.006 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".